# Drone on Kubernetes with Docker plugin: Strange network problem

**URL:** <https://drone.discourse.group/t/drone-on-kubernetes-with-docker-plugin-strange-network-problem/10946>\
**Category:** Drone Support\
**Created:** [November 28, 2020, 1:52am UTC](https://drone.discourse.group/t/drone-on-kubernetes-with-docker-plugin-strange-network-problem/10946 "2020-11-28T01:52:28Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![BigeYoung](https://yyz1.discourse-cdn.com/flex003/user_avatar/drone.discourse.group/bigeyoung/32/2985_2.png) [@BigeYoung](https://drone.discourse.group/u/BigeYoung)\
**Post date:** [November 28, 2020, 1:52am UTC](https://drone.discourse.group/t/drone-on-kubernetes-with-docker-plugin-strange-network-problem/10946/1 "2020-11-28T01:52:28Z")

</div>

Dockerfile:

```auto
FROM php:7.4-apache
RUN pecl install grpc

```

.drone.yml

```auto
kind: pipeline
type: kubernetes
name: default

steps:
- name: install
  image: composer
  commands:
  - composer install
- name: docker
  image: plugins/docker
  settings:
    repo: ……

```

drone output:

```auto
Step 2/9 : RUN pecl install grpc
 ---> Running in 0b61c6790db4
No releases available for package "pecl.php.net/grpc"
install failed
The command '/bin/sh -c pecl install grpc' returned a non-zero code: 1
time="2020-11-28T01:29:26Z" level=fatal msg="exit status 1"

```

But I tried `docker build .` directly on my server, pecl can install grpc.

---

<div class="post-metadata">

**Author:** ![BigeYoung](https://yyz1.discourse-cdn.com/flex003/user_avatar/drone.discourse.group/bigeyoung/32/2985_2.png) [@BigeYoung](https://drone.discourse.group/u/BigeYoung)\
**Post date:** [November 28, 2020, 6:19am UTC](https://drone.discourse.group/t/drone-on-kubernetes-with-docker-plugin-strange-network-problem/10946/2 "2020-11-28T06:19:53Z")

</div>

In **.drone.yml**

```auto
kind: pipeline
type: kubernetes
name: default

steps:
- name: test
  image: composer
  commands:
  - ping pecl.php.net

```

SUCCESS!

in **Dockerfile** in **plugins/docker** in **Drone** on **Kubernetes**

```auto
RUN ping pecl.php.net

```

FAILED.

---

<div class="post-metadata">

**Author:** ![csgitharness](https://yyz1.discourse-cdn.com/flex003/user_avatar/drone.discourse.group/csgitharness/32/904_2.png) [@csgitharness](https://drone.discourse.group/u/csgitharness)\
**Post date:** [December 1, 2020, 12:20pm UTC](https://drone.discourse.group/t/drone-on-kubernetes-with-docker-plugin-strange-network-problem/10946/3 "2020-12-01T12:20:06Z")

</div>

Hi, Could you please check and confirm if you are able to ping [pecl.php.net](http://pecl.php.net) from the container/Kubernetes cluster directly.

---

<div class="post-metadata">

**Author:** ![bradrydzewski](https://yyz1.discourse-cdn.com/flex003/user_avatar/drone.discourse.group/bradrydzewski/32/3513_2.png) [@bradrydzewski](https://drone.discourse.group/u/bradrydzewski)\
**Post date:** [December 1, 2020, 3:41pm UTC](https://drone.discourse.group/t/drone-on-kubernetes-with-docker-plugin-strange-network-problem/10946/4 "2020-12-01T15:41:43Z")

</div>

The docker plugin uses docker-in-docker. In order for the docker-in-docker daemon to inherit dns settings you may need to set the plugins mtu value (see the plugin documentation for a list of available settings). From this relevant thread [Issue - Kubernetes Runner - Cert validation issues with Plugin/Docker](http://discuss.harness.io/t/issue-kubernetes-runner-cert-validation-issues-with-plugin-docker/7712)

---

<div class="post-metadata">

**Author:** ![BigeYoung](https://yyz1.discourse-cdn.com/flex003/user_avatar/drone.discourse.group/bigeyoung/32/2985_2.png) [@BigeYoung](https://drone.discourse.group/u/BigeYoung)\
**Post date:** [December 4, 2020, 8:42am UTC](https://drone.discourse.group/t/drone-on-kubernetes-with-docker-plugin-strange-network-problem/10946/5 "2020-12-04T08:42:24Z")

</div>

Thank you very much for @bradrydzewski 's answer!  
MTU is the key to solving the problem. Happily, this problem can be solved easily. For those who are still troubled by this question, the answer to the question is:

```
kind: pipeline
type: kubernetes
name: default

steps:
  - name: dockerize
    image: plugins/docker
    settings:
      ...
      mtu: 1000
```